Detection of a gas leaked into a liquid which has been sampled from a plurality of spaces

ABSTRACT

A method for discovering amounts of halogen in a liquid is provided wherein the a reservoir comprising the liquid and suspected halogen is healed to a temperature characteristic of the solubility of halogen in the liquid to provide a vapor. After condensing, a sampling vapor is provided to from which the amount of halogen may be detected.

This is a continuation of copending application Ser. No. 07/477,309filed on Feb. 8, 1990, U.S. Pat. No. 5,115,666.

FIELD OF THE INVENTION

The present invention relates to detection apparatus and methods. Inparticular, the invention relates to apparatus and methods for detectingthe presence of halogen gases dissolved in a liquid such as water.

BACKGROUND OF THE INVENTION

In industrial systems, and particularly, in refrigeration systems, themixture of water with liquid refrigerants is undesirable. For example,the presence of excess water in liquid refrigerants may freeze at lowtemperatures and restrict or completely prevent the flow of expansionvalves, capillary tubings, and the like.

In addition, the solubility of amounts of refrigerant in liquids such aswater is of considerable concern in refrigeration systems such asdrinking water coolers, water cooled condensers and the like where smallamounts of the refrigerant are introduced with water or other liquidseither through equipment failure, or in some instance, by faulty design.The presence of excess water in halogen may cause corrosion in thesystem. In particular, such water may cause the hydrolysis of leakyhalogenated refrigerant with the formation of acids. These acids tend tocorrode metals as well as insulation and nonmetallic parts of thesystem. This condition is especially problematic during charging of therefrigeration system. Accordingly, detection of the halogen contaminantis essential to the operation and maintenance of these systems.

In a typical refrigeration system, there are at least first and secondloops. The first is a closed loop for circulating a refrigerant,typically a well known halogen refrigerant. The first, refrigerant loopincludes a motor-driven compressor for compressing the inputted halogen,thus converting the halogen refrigerant from a gaseous to a liquid stateand outputting a heated halogen liquid. The heated halogen liquid issupplied to a condenser, which cools the halogen liquid. Typically, suchcondensers include a serpentine shaped tube, typically made of copper,for receiving and circulating the warm liquid halogen, and a shell forenclosing the serpentine shaped tube and circulating water thereabout,whereby the liquid halogen is cooled. The cooled liquid halogen is nextdirected through an expansion valve and into an evaporator. The valvecauses the liquid halogen to expand and to change from a liquid to agaseous state within the evaporator. As the halogen changes from agaseous to a liquid state, it absorbs heat thereby providing significantcooling. The cooled halogen gas is returned through the first loop fromthe evaporator to the compressor, whereby this cycle continues.

A trouble point in such refrigeration systems occurs in the condenserwhen the water circulating over the copper tubing wears by frictionbetween the water and the tubing holes in the tubing, thereby causing amixture of the halogen and water. Most (but not all) refrigerants arecirculated in the first, refrigeration loop under positive pressure sothat when a leak occurs in the condenser tubing, halogen will flow intothe cooling water and dissolve the water therein. The second loop inwhich the cooling water flows varies from refrigeration system torefrigeration system. In some systems, the cooling water may be drawnfrom a river and after cooling returned to the river. In other systems,the cooling water may be passed to a cooling tower and allowed to falldown over a series of baffles. Typically, such water towers are open tothe atmosphere, whereby if there has been a halogen leak, the solutionof water and halogen is exposed to the atmosphere and halogen will bereleased into the atmosphere with possible damage to the environment andin particular to the ozone layer.

In those refrigeration system where the refrigerant is maintained undera negative pressure, water will be drawn through the holes into thefirst, refrigerant loop. Thereafter, the solution of water and halogenis returned from the evaporator to the condenser. Significant cooling ofthat solution takes place in the evaporator, whereby the water isconverted to ice. When that ice is introduced into the compressor, theice may readily damage the compressor and its motor, thereby bringingthe operation of that refrigeration system to a halt.

Alternatively, there are refrigerant systems which incorporate anevaporator acting as a heat exchange device, whereby the expandinghalogen gas passes through the evaporator in the form of a serpentineshaped coil surrounded by a shell for receiving a liquid, typicallywater, to be cooled. The water circulating over the evaporator tube maycause holes to wear therein, whereby a mixing of the halogen and wateroccurs. In such an embodiment, the cooled water is typically circulatedthrough a second closed loop to cool an environment and thereafterreturn to be recooled by the evaporator. As described above, thepresence of water and halogen is particularly corrosive. In thoseinstances where the refrigerant is positively pressurized, halogen willbe forced through the tube holes into the second closed cooling loop,thus contaminating the circulated water. Eventually, there is a strongpossibility that the second loop will be corroded to the extent thatholes will develop therein, whereby the water contaminated with halogenwill leak directly into the surrounding environment. Again, possiblecontamination of the environment is likely.

In either of the above described refrigeration systems, wearing andcontamination may occur with the result that water may becomecontaminated with the halogen. Therefore, it is important to be able todetect the presence of water dissolved in halogen so that contaminatedrefrigeration systems may be shut down and detected leaks of halogenrepaired.

Prior art approaches to similar problems of this nature require heatingthe sample water having suspected contamination to temperatures by whichthe water may be expanded and thereby introduced to sensing apparatus.U.S. Pat. No. 4,154,086 to Button et al describes such an approach forthe detection of volatile organic compounds such as hydrocarbons inwater solutions used in petrochemical systems. A carrier gas such asnitrogen is introduced into the water solution containing thehydrocarbons. The water solution is thereafter heated to elevatedtemperatures in excess of 150° F., whereby a water vapor solutioncontaining the carrier gas and hydrocarbons is formed. After acondensing step, the remaining hydrocarbons are applied to a detector.

Generally, however, the solubility of halogenated refrigerants in wateris an important consideration in the detection of the amount of halogenpresent. At extreme temperatures, the solubility of halogen in water andother liquids increases and it becomes increasingly difficult tocondense the vapor solution to separate the halogen from the water foraccurate detection. Accordingly, while prior art approaches may providesatisfactory solutions for their intended uses, they are incapable ofdealing with the problem of detection of amounts of a halogen in aliquid.

OBJECTS OF THE INVENTION

It is therefore a general object of the present invention to provide animproved method for detecting halogenated gases in a liquid.

It is an additional object of the present invention to accurately detecttrace amounts of halogen gases in a liquid.

A further object of the invention is to minimize the solubility of aliquid in a halogen gas for increased accuracy in the detection ofsubsequently released halogen.

An additional object of the present invention to provide a method fordetecting halogenated gases in a liquid for continuous monitoring ofsuch gases.

A still further object of the present invention is to provide a methodfor detection which is capable of more accurate and quantitativemeasurement than is heretofore known.

Other objects and advantages of the invention will become apparent uponreading the following description and appended claims, and uponreference to the accompanying drawings.

SUMMARY OF THE INVENTION

These objects are achieved with a method of discovering amounts ofhalogen in a solution of halogen and a liquid that uses a minimizedevaporation temperature of the solution to reduce the solubility of theliquid in halogen. The method according to the present inventionaccomplished this by providing a sample of the liquid in a reservoir.The reservoir is heated to an evaporation temperature attributable tothe solubility of the liquid in halogen to provide a vapor solution ofhalogen and liquid. The vapor solution is thereafter condensed to removea portion of the liquid and provide a sampling vapor. In this way, anamount of halogen may be detected in the sampling vapor.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this invention, reference shouldnow be made to the embodiment illustrated in greater detail in theaccompanying drawings and described below by way of example of theinvention.

FIG. 1 is a block diagram representation of a halogen leak detectionapparatus in accordance with the present invention.

FIG. 2 is a schematic representation of the halogen leak detectionapparatus of FIG. 1 showing its components in one arrangement of thepresent invention.

FIG. 3 is a diagrammatic representation of the electrical circuitelements in the leak detection apparatus of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following detailed description will permit a more completeunderstanding of this invention. However, the embodiment described belowis simply an example of the invention, and the invention will not belimited to this embodiment. It will be understood that the methods andapparatus of the invention may be implemented with the use of variousconfigurations with appropriate modification. It will be furtherunderstood, that in certain instances, details may have been omittedwhich are not necessary for an understanding of the present invention.

Generally, the present invention relates to a method for detecting thepresence of halogen in a solution of halogen and a liquid. The presentinvention uses information related to the solubility of the liquiddissolved in halogen for setting an appropriate evaporating temperatureof the solution. By so doing, the amount of the evaporated liquid iscontrolled. In addition, the halogen detecting means used by the presentinvention may detect small amounts of halogen with increased accuracy.The apparatus and method according to the preferred embodiment samples aliquid solution comprising water. It will be understood by those skilledin the art to which this invention pertains, that other liquids such asbrine or glycol may be sampled just as easily with slight modification.

Turning now to the drawings, FIG. 1 shows a block diagram representationof a halogen detecting apparatus 10 according to the present invention.A liquid such as water having a suspected amount of halogen gas to bedetected is directed from a source (not shown) into a fluid inlet 12. Inan illustrative application, the inlet 12 may be coupled to receivewater from the discharge side of a condenser disposed in the first,refrigerant loop of the refrigeration system as described above. Anactuable valve 14, in communication with the fluid inlet 12 directs theliquid through a fluid manifold 18. A controller 22 provides appropriatecontrol signals to actuate or deactuate the valve 14 to control theamount of liquid provided to the fluid manifold 18. Upon receiving theliquid, the fluid manifold 18 provides a passageway to a fluid reservoir26.

A heating element 30 associated with the fluid reservoir 26 controls thetemperature of the liquid solution dependent upon the solubility of theliquid in that gas. The heating element 30 heats the solution to aminimum temperature to release a vapor solution of water and halogen.The vapor solution is directed to a dehumidifier 36 for removingremaining water from the vapor solution and thereafter, to provide asampling vapor for detection. The dehumidifier 36 also receives controlsignals provided by the controller 22.

A halogen gas detecting device 40 detects the amount of halogen derivedfrom the dehumidifier 36 and thereafter provides an output signal on aline 44 indicative of the amount of halogen detected.

Turning now to FIG. 2, therein is shown a schematic representation ofthe detecting apparatus 10 of the present invention. As shown in FIG. 2,the detecting apparatus 10 may be conveniently placed on a movableindustrial cart 46 or other suitable means for easy portability.

A source of liquid is received from a water cooled condenser, chillerbarrel, or other industrial refrigerant vessel (not shown) having asuspected presence of a halogenated gas. Refrigerants stored in suchcylinders, receivers, condensers and the like achieve an equilibriumbetween a liquid and gaseous state. With most halogenated refrigerants,the concentration of water in the gaseous portion is greater than in theliquid phase. Accordingly, the refrigerant becomes wetter as the vaporis removed.

With certain refrigerants, however, the situation is reversed. The ratioof concentration of water between the vapor and liquid is higher at lowtemperatures than at higher temperatures. This distribution of waterresults in a drier remaining liquid when the vapor is removed from thecontainer. Since a higher concentration of water is removed with theremoval of the vapor, a refrigerant changed in this way will have ahigher concentration than that originally in the container.

The liquid having a suspected presence of halogenated refrigerant entersthe fluid inlet 12 in communication with a plurality of actuable valves16a through 16f. Preferably, the valves 16a through 16f are solenoidvalves suited for most types of industrial applications and used forwater, light oils, air lines and the like. With the use of a pluralityof valves, multiple sources of sampling liquid may be introduced to thedetection apparatus 10. Of course, the present invention could work justas easily with one valve receiving liquid from a singular source. Astainless steel insert (not shown) may be used for protection when theliquid source contains glycol type solutions which tend to otherwisecorrode the actuable valves 16a through 16f. For example, one valve 16acould control the input of water from the discharge side of thecondenser and a second valve 16b could control the input of liquid fromthe discharge of the evaporator of that refrigeration system describedabove.

In the preferred embodiment, the valves 16a through 16f are mounted tothe manifold 18 comprising a single manifold body 19 having multiplereceiving ports 18a through 18f formed to receive the valves 16a through16f, respectively. In this way, the output of the valves 16a though 16fis directed into the manifold 18.

A programmable controller or sequencer 22 provides control signals tothe valves 16a through 16f to actuate a desired valve and to control theamount of liquid introduced to the detecting apparatus 10. In thepreferred embodiment, the programmable controller 22 is an SLC 100processor unit manufactured by Allen-Bradley, having a centralprocessing unit, RAM memory, a power supply, and battery backup powersupply as will be understood by those skilled in the art.

A timer counter access terminal may be used in conjunction with thecontroller 22 to access programmed timer, counter and sequencer data.This feature advantageously allows production, supervisory, andmaintenance personnel to monitor data generated by the detectingapparatus on a real-time basis. Preferably, I/O addresses may also beaccessed such that appropriate software modification may be provided tothe controller 22 to accommodate varied processes or part changes. Inaddition, a key switch 50 may be provided to gain access to functions ofthe controller 22, thereby preventing unauthorized modification.

From receipt of control signals provided by the controller 22, thevalves 16a through 16f direct the fluid through the manifold 18 into asampling reservoir 26. The reservoir is contained in a sampling tank 52,preferably fabricated of stainless steel of 0.08 gauge having dimensionsof a height of approximately nine inches and a base 60 dimensioned fiveinches wide by ten inches long.

A float assembly 54 including a float valve 56 is positioned within thesampling tank 52 to prevent the liquid reservoir 26 from overflowing.When the amount of liquid exceeds a threshold level as determined by thefloat valve assembly 54, the float valve 56 closes to prevent excessliquid from entering the liquid reservoir 26. A Robert Valve ActionFloat Assembly manufactured by Robert Valves is preferred.

The liquid reservoir 26 within the sampling tank 52 maintains a flowrate of approximately one half gallons per minute. The liquid exits thesampling tank via an open drain 58.

A submersible heater 30 is mounted to the base 60 of the sampling tank52, and is preferably controlled with the use of a thermostat 92. Thethermostat 92 maintains the liquid reservoir 26 at a selectedtemperature illustratively not less than 70° F. As will be explained,the selected temperature is carefully set to ensure that trace amountsof the halogen may be accurately detected, dependent upon the solubilityof the liquid, typically water, in the refrigerant, illustratively ahalogen.

A table detailing the solubility in water of commercially availablehalogen refrigerants, which are denoted as "R-₁₃ " as will be understoodby those skilled in the art, is shown in the Table below:

                  TABLE                                                           ______________________________________                                        SOLUBILITY OF WATER IN LIQUID REFRIGERANTS                                    Solubility in Parts per Million by Weight                                     Temp., °F.                                                                     R-11    R-12    R-22  R-113 R-114  R-502                              ______________________________________                                        100     168     165     1800  168   148    740                                80      113     98      1350  113   95     560                                60      70      58      970   70    57     440                                40      44      32      690   44    33     300                                20      26      17      470   26    18     185                                 0      15      8       308   15    10     120                                -20     8       4       195   8     5      70                                 -40     4       2       120   4     2      40                                 -60     2       1       68    2     1      20                                 -80     >1      >1      37    >1    >1     12                                 ______________________________________                                    

From the above Table, it is seen that if the values of solubility ofwater in these halogen refrigerants in parts per million (ppm) wereplotted as a function of temperature, that each of the listed halogenrefrigerants would have a curve comprising a first portion slopingupward at a first rate to a certain point or knee, and a second portioncontinuing upward from the knee at a second rate greater than the first.By observation of the above chart, it can be seen that the knee of thecurves generally falls between 70° and 100° F. The selected temperatureat which the water within the reservoir is heated is determined basedupon the solubility of water in halogen and is typically set in therange of 70° and 100° F. and optimally at 75°. If the evaporationtemperature is increased beyond this range, it can be seen that the ppmof water will significantly increase as a function of temperature. Thusat such elevated temperatures, the released vapor solution of water andhalogen contains a relatively high percentage of water vapor, which willpotentially interfere with the subsequent measurement of halogen by thedetector 40. On the other hand, if the temperature is decreased belowthis range, significantly lower amounts of halogen are released and themeasurements of such minimal amounts may be inaccurate. Thus, theprocess of sensing the halogen is optimized by setting the selectedevaporation temperature of the solution within the reservoir 30 at anoptimum temperature at or just below the knee of the curve of thesolubility of water in the refrigerant as a function of temperature.

Inasmuch as the liquid reservoir 26 is a typical volume liquid within anopen container (sampling tank 52), it has been found that temperaturesabove 70° F. provide better escaping moisture vapors. It has been foundthat for solutions of halogen and water, the evaporation temperatureshould not be greater than 100° F., and preferably does not exceed 75°F. As the temperature is increased, the halogens to be detected becomemore soluble in water and it becomes increasingly difficult to condensethe vapor solution to separate the halogen from the water in asubsequent condensing step. The arrangement in the present inventionadvantageously minimizes the solubility of the halogen in the water,whereby most of the water vapor may be condensed leaving relatively purehalogen gases to be detected during subsequent condensing of the vaporsolution.

As particularly shown in FIG. 2, the detecting apparatus 10 is placedupon the industrial cart 46, which includes a horizontally disposedtable surface 29. The tank 52 for containing the sampling reservoir 26is mounted below the surface 29 and in communication with an opening 67therethrough. An enclosure 62 is mounted on top, as shown in FIG. 2, andincludes a centrally disposed partition 61 dividing the enclosure 62into a first chamber 63 and a second chamber 65. The first chamber 63 isaligned with the opening 67 to receive the vapors expelled from thesampling reservoir 26. These vapors are drawn from the chamber 63 to thedehumidifier 36, such as an EBAC Industrial Humidifier Model No. CD-30.As is typical within such a dehumidifying device, an evaporator coil 64is mounted adjacent a condenser 66. The evaporator coil 64 evaporatesapproximately 50% of the water present within the sampling vaporprovided by the liquid reservoir 26. An additional 5 to 10% of the waterwithin the vapor is eliminated by heat generated by the condenser 66.The dehumidifier 62, as illustratively identified above, comprises acompressor 78 for circulating a refrigerant through an output line 57 tothe condenser 66, wherein the refrigerant expands within the evaporativecoil 64 to cool the vapor introduced into the first chamber 63, to atemperature illustratively set at 37° or 38°. At such a temperature, thecondenser coil 64 removes approximately 50% of the water vapor from thesolution vapor. Thereafter, the refrigerant returns to the condenser 66,wherein the refrigerant is heated to a temperature in the order of 110°F. The vapor is drawn by the fan 68 over the condenser 66, whereby thevapor is subjected to a further, second step of dehumidification,whereby approximately 5% to 10% of the water vapor is further removed.The refrigerant is returned through a line 55 to the compressor 78,whereby this cycle continues.

The vapor is drawn into the condenser 66 with the use of condenser fan68 in the direction denoted by the arrow 70. As will be appreciated bythose skilled in the art to which this invention pertains, an air filter72 is placed at an entrance to the enclosure 62. The fan 68 is capableof drawing the ambient atmosphere through the filter 72 into the firstchamber 63, whereby the presence of halogen in the ambient atmosphere,as well as the vapor expelled from the reservoir 26, may be detected.The velocity of the ambient atmosphere (air) flow passing over thereservoir sampling tank 52 is, in the preferred embodiment,approximately 50 feet per minute.

The halogen gas molecules in the vapor are quite stable. Accordingly,these molecules do not condense in the dehumidification process. Thesampling air expelled from the condenser 66 maintain approximately40-50% relative humidity, i.e., approximately 40-50% of the water withinthe vapor does not condense. As a result, a sampling vapor containingany halogen gases that may be present is provided.

The evaporation rate per ASHRAE is 3.5 pints per day, and may berepresented by the following equation: ##EQU1## where: W=1 lb./hourevaporated

A=surface area (2 square feet)

v=velocity on surface (50 feet/sec.)

Y=latent heat of vapor (1045 BTU/10)

Pw=Vapor pressure H₂ O (1.213 inches Hg)

Pa=Vapor pressure ambient (0.522 inches Hg)

A relative humidity transmitter 73 is positioned downstream of thedehumidifier 36. The transmitter 73 continuously monitors and displaysthe relative humidity of the sampling air. In the preferred embodiment,the transmitter 73 is preset with a threshold of 80% relative humidity.If the relative humidity exceeds 80%, the transmitter 73 provides adisable signal to the controller 22. If the relative humidity shouldexceed 80%, there is a strong likelihood that the gas detector 40 maymalfunction. The detector 40 of a preferred embodiment is fullydescribed in copending U.S. Ser. No. 134,293, now U.S. Pat. No.4,910,463, incorporated herein by reference. The detector 40 describedtherein employs a sensor which detects halogen based upon an increasedionization in the presence of halogen. In particular, halogen is passedbetween anode and cathode elements of the sensor. Halogen is detected byan increase in the ionization current drawn from the cathode element. Ifsuch a halogen sensor were employed, a vapor having a relatively highhumidity in excess of 80% may well cause the sensor to malfunction and,in particular, to cause a discharge between the cathode and anodeelements. Such a discharge, due to the presence of a relatively lowconductive path between the sensor elements, will give an erroneousreading and may well cause damage to the sensor itself. As disclosed inthe noted application, the detector 40 upon detecting halogen abovepredetermined levels will automatically disconnect power from its sensorto avoid damage thereto. Upon receipt of such information, thecontroller 22 may provide appropriate signals to sound an alarm or forother devices to indicate that the dehumidifier 36 has malfunctioned.The noted disabling signal provided by the detector 40 may also be usedas a control signal to turn off the fan 68. It will be appreciated thatthe relative humidity transmitter 73 may also have indication means suchas an LED display for visual monitoring by operating personnel.

However, if the relative humidity of the sampling vapor is within thelimits set by the relative humidity transmitter 73, the sampling vaporis directed to the halogen gas leak detector 40. As shown in FIG. 2, theenclosure 62 confines and directs the dehumidified vapor to an inlet 71of the detector; in turn, the vapor is directed to a sensor (not shown),which operates as described in the above-identified application to sensethe presence of halogen. The detector 40 analyses the sampling vapor inppm and includes variable trip point settings which may be preselected.Accordingly, if a desired trip point setting is exceeded from thedetection of the concentration of halogen gas in the sampling air, thedetector 40 sends appropriate signals via analog, digital, or drycontact communication to indicate an undesired concentration of halogengas.

Inasmuch as the detector 40 comprises a resident microprocessor, thedetector 40 may concurrently provide signals to the actuating valves 16athrough 16f. In this way, the actuating valves 16a through 16f maybecome deenergized, causing the valves 16a through 16f to close andpreventing further liquid from entering the detecting apparatus. In thiscondition, the fluid reservoir 26 drains through the open drain 58.Appropriate signals may be concurrently applied to the dehumidifier 36for deactivating the same.

Turning now to FIG. 3, therein is shown a simplified electricalschematic diagram of the present invention. A conventional power source76 supplies electrical power to the controller 22, the heater 30, theactuated valves 16a through 16f, a compressor 78 in the dehumidifier 36,and the halogen leak detector 40. The thermostat 92 controls thetemperature of the heater 30 via the line 94. The humidity transmitter73 upon sensing excess humidity applies signals to shutdown the halogenleak detector 40 and the dehumidifier 36 via the lines 96 and 98respectively. In particular, the fan 68 is deactivated upon sensingexcess humidity to prevent possible damage to the detector 40 and itssensor. The controller 22 provides central signals to the actuatedvalves 16a through 16f via the line 24. The halogen leak detector 40provides signals to actuate an appropriate alarm (not shown) via theline 44. Further, the detector 40 applies a signal via line 93 to open arelay switch 95, whereby the circuit formed by the lines 24 to thesolenoid valves 16 is opened and the valves 16 are closed. Thus, it isseen that when the halogen leak detector 40 senses a preset level ofhalogen dependent upon the refrigerant employed, the detector 40 willcause the solenoids 16 to close, thereby preventing further liquid to bebrought to the sampling reservoir 26.

EPA standards have been established for each of the refrigerants. Asdescribed in the above noted application, threshold levels of halogengas may be variously set to be detected, whereby this apparatus 10 maybe used for various refrigerants. For example, the refrigerant R12 has atoxicity level of 1000 ppm, whereas the refrigerant R23 has a thresholdlevel of 100 ppm.

In use, the cart 46 and the apparatus 10 may be moved to a selectedlocation having an environment whose halogen level needs to bemonitored. In one illustrative use, the apparatus may be convenientlydisposed within the compressor room of a large refrigeration system asdescribed above. At least one of the solenoid valves 16 may be connectedto the discharge side of the condenser as disposed in the refrigerantloop of that system. If there has been a leak of the halogen from therefrigerant loop the water and halogen solution is directed via theselective valve 16 to the sampling reservoir 26, where it is heated andvapors are released and drawn through opening 27 into the dehumidifier36. After a two-step process of water vapor removal, the relativelywater free halogen vapor is directed to the gas detector 40.

In addition, the apparatus 10 of this invention is also capable ofmeasuring the presence of halogen in the ambient atmosphere thereabout.In such an application, an airflow as indicated by the arrows 70 isdrawn through the filter 72 into the first chamber 63. This airflow isdirected by the condenser fan 68 to the detector 40, which is alsocapable of detecting halogen in that flow. Initially, when the detector40 responds to a level of halogen above the set threshold, the operatordoes not know whether the indicated halogen leak is from the water drawnfrom the condenser or from the ambient atmosphere within the compressormotor room. After the first alarm, the operator (or it could be doneautomatically) shuts off the related valve 16 and the monitoring processcontinues. If the halogen detector 40 again indicates the presence ofhalogen above the threshold value, the second detection indicates thatthe halogen was present in the airflow. Conversely, if the detector 40does not indicate again the presence of halogen after the solenoid valve18 has been closed, there is an indication that the halogen leak wasfrom the condenser.

A novel detecting apparatus and method meeting the aforestated objectshas therefore been described. The invention detects the amount ofhalogen in a liquid by controlling the temperature of the solution inaccordance with properties characteristic of the halogen gas to bedetected bearing upon its solubility in that liquid. It will beunderstood by those skilled in the art to which this invention pertainsthat various modifications may be made in detail and arrangement of theprocesses and of the structures described herein in order to explain thenature of the invention without departing from the principles of theforegoing teachings. Accordingly, the invention will only be limited asexpressed in the appended claims.

What is claimed is:
 1. Apparatus for taking samples of a liquid from aplurality of corresponding spaces and monitoring the samples of liquidto detect a leak into the liquid of a given gas of a given concentrationlevel which is greater than a residual level of the given gas, saidapparatus comprising:a) a plurality of actuable valves, each of saidvalves in communication with a respective one of said plurality ofspaces; b) a common sampling reservoir in communication with each ofsaid plurality of valves for receiving the sample of the liquid from anactuated one of said plurality of valves; c) means for separating thegiven gas present in the liquid of the sample in said samplingreservoir; d) gas detecting means in communication with said samplingreservoir for detecting the presence of the separated gas of aconcentration above the given concentration level to provide an alarmindicative of a valid leak of the given gas into a corresponding liquidsample; and e) controlling means including means coupled with each ofsaid plurality of actuable valves for selectively actuating one of saidplurality of valves to permit the introduction of one sample of theliquid at a time from the corresponding one of said plurality of spacesinto said sampling reservoir and the subsequent detection by said gasdetecting means of the separated given gas in the one sample.
 2. Theapparatus of claim 1, wherein said controlling means includes means fordeactuating said one actuated valve in response to said alarm.
 3. Theapparatus of claim 1, wherein there is further included actuatable fanmeans disposed in communication with said sampling reservoir forconveying the separated given gas to said gas detecting means, and saidcontrolling means is responsive to said alarm for deactuating said fanmeans.
 4. The apparatus of claim 1, wherein there is further includeddrain means attached to a bottom portion of said sampling reservoir. 5.The apparatus in claim 1, wherein there is included means for limitingthe volume of the sample of the liquid introduced into said samplingreservoir to a given level.
 6. The apparatus in claim 5, wherein saidlimiting means comprises means for sensing the liquid level within saidsampling reservoir above said given level to apply a deactivating signalto said controlling means, whereby said one activated valve isdeactivated.
 7. A method for taking samples of a liquid from a pluralityof corresponding spaces and monitoring the samples for the suspectedpresence of a given gas leaked into the liquid in any of said pluralityof spaces of a given concentration level greater than a residual levelof the given gas, said method comprising the steps of:a) taking onesample of the liquid at a time from a selected one of the plurality ofspaces and introducing the one liquid sample into a common samplingreservoir; b) separating the given gas present in the liquid of the onesample introduced into the sampling reservoir; c) conveying the givengas separated into the sampling reservoir to a sensor; and d) operatingthe sensor to detect the presence of the given gas separated from theone sample of a concentration above the concentration level to producean alarm indicative of a valid leak of the given gas into acorresponding liquid sample.
 8. The method of claim 7, wherein thesample introduced into the sampling reservoir is removed before the nextsample from another space of the plurality is introduced thereto. 9.Apparatus for taking samples of a liquid from a plurality ofcorresponding spaces and monitoring the samples of liquid to detect aleak into the liquid of a given gas of a given concentration level whichis greater than a residual level of the given gas, said apparatuscomprising:a) a single conduit having a plurality of ports therein; b) acorresponding plurality of actuable valves, each of said valves incommunication with a respective one of said plurality of spaces and arespective one of said plurality of ports; c) a common samplingreservoir coupled to said single conduit for receiving the sample of theliquid from an actuated one of said plurality of valves; c) means forseparating the given gas present in the liquid of the sample in saidsampling reservoir; d) gas detecting means in communication with saidsampling reservoir for detecting the presence of the separated gas of aconcentration above the given concentration level to provide an alarmindicative of a valid leak of the given gas into a corresponding liquidsample; and e) controlling means including means coupled with each ofsaid plurality of actuable valves for selectively actuating one of saidplurality of valves to permit the introduction of one sample of theliquid at a time from said corresponding one of said plurality of spacesinto said sampling reservoir and the subsequent detection by said gasdetecting means of the separated gas in the one sample.